Merge branch 'jk/cached-commit-buffer' into HEAD

* jk/cached-commit-buffer:
revision: drop --show-all option
commit: drop uses of get_cached_commit_buffer()
Git 2.16.2

diff --cc builtin/rev-list.c
Simple merge

diff --cc log-tree.c
Simple merge

diff --cc revision.c
Simple merge

diff --cc revision.h
Simple merge